Containers for a wide variety of products typically have been made of glass, steel or aluminum. In the beverage industry today, the smaller containers usually are made of aluminum, while PET plastic containers currently are used for larger sizes (1 and 2 liters, for example). While many applications for steel, aluminum or paperboard containers exist, these containers are not suited for applications where it is desirable for the contents to be visible through the container. In this latter case, glass containers have been in widespread use for many years.
A major disadvantage of glass containers, however, is that the containers necessarily are quite heavy if they are manufactured to be sufficiently strong to resist breakage. Even so, breakage is a common occurrence with glass containers; and the weight of glass containers significantly increases the shipping costs of whatever product is packaged within them.
Because of the inherent disadvantages of glass containers, the use of strong distortion-free lightweight plastic PET containers for products such as condiments, cosmetics, perfumes and the like has increased.
Machines for manufacturing clear PET plastic bottles or jars of the type widely used for mayonnaise, mustard, vegetables, pickles, cosmetics, perfumes and the like, typically are multi-stage molding machines. Frequently, the bottles or containers which are formed by these machines are clear, colorless plastic. In many applications, the bottle or container must be flawless (that is it must be without scratches or other imperfections) or it will be rejected by the packer who uses the container for packaging its product.
In prior art multi-stage PET bottle making machines, the bottles formed by the machine are released from the final stage, and are permitted to drop into a bin or container located beneath the machine, or are dropped onto a slide which directs them to a bin or container located adjacent the machine. Whichever of these prior art techniques are used, the bottles or containers fall against one another in random positions and must be removed from the containers by some means, typically manually, and packed for shipping. Alternatively, the bottles or containers are removed from the bins into which they are dropped; and they are placed on a conveyor or other apparatus for transport to a filling machine. All of this handling and the dropping of newly formed bottles into the container on top of bottles already in the container, results in scratches and damage to the bottles. Consequently, additional inspection is required; and containers are rejected as a result of damage caused by dropping them from the molding machine.
Various types of lifting and transporting mechanisms using vacuum pickup heads have been devised for various applications for moving articles from one point to another with minimum mechanical contact to the article being transported or moved by the mechanism. The patent to Ammon U.S. Pat. No. 3,033,604 is directed to a vacuum device for lifting and transporting cylindrical articles. The device of Ammon includes a centering ring surrounding the vacuum pickup heads; so that the articles are accurately located in the device. Nothing is inserted into the interior or open end of an article being moved; but the device makes contact with the closed end of a cylinder.
The patents to Hawkswell U.S. Pat. No. 4,610,473; Mang U.S. Pat. No. 4,650,233; Ragard U.S. Pat. No. 4,705,311; and Stannek U.S. Pat. No. 4,858,954 all are directed to different types of vacuum pickup devices, many of them used in the electronics industry for transporting integrated circuit parts from one position to another. None of these patents, however, are directed to a mechanism for transporting or handling open-ended containers such as plastic PET bottles.
It is desirable to provide a mechanism for use with a molding machine, particularly a PET molding machine, which overcomes the disadvantages of the prior art mentioned above, which is simple and effective in operation, and which eliminates the dropping and random orientation of bottles delivered from the final stage of such machines.